Bloat (frothy)

What to look for

If found before death: distended abdomen on the left side between the last rib and the hip bone very distressed, difficulty breathing if untreated, may die quickly

Cows can also have less severe forms of bloat that may depress milk production

Cause

Consumption of young, rapidly growing legumes, clover or lucerne. Bloat is usually caused by eating pasture species that are growing quickly and contain low fibre levels. Consequently, animals produce less saliva production which makes them more susceptible to bloat. Under certain circumstances, feeding on these pastures can lead to build up of foam in the rumen that prevents animals burping to remove the gas produced in the rumen.

Animals likely to be affected

Heifers are more likely to die of bloat than older cows. There may be breed differences in susceptibility, with Jerseys and crossbred cattle being more susceptible.

Other diseases with similar signs

Other causes of sudden death.

Confirming the diagnosis

Sudden death of animals with very distended abdomens (this is only useful in diagnosis if the animal has died recently because all animals will blow up after death)
Recently introduced to pastures with a high clover or lucerne content. Characteristic foam in the rumen (but this only lasts for a few hours after death)

Treatment

Move animals from the toxic pasture to a pasture with lower levels of clover or lucerne

Provide supplementary feed such as hay or silage
Animals that are mildly affected can be treated with a bloat drench.

In advanced cases of bloat it is often difficult to administer treatments that will reduce foam in the rumen.

As a last resort, an incision can be made in the upper left flank to allow the foam to escape. While this approach may save the bloated animal it is essential to call your vet immediately to repair the wound and administer antibiotics to counter infection.

Bluetongue

What to look for - Australian strains cause no signs of disease

Virulent bluetongue virus may cause fever, small ulcers and bleeding in the mouth and nose, dribbling of saliva and nasal discharges.

Cause - an insect-borne virus

There are 24 different types of bluetongue virus and, of these, 10 have been found in Australia. We need to keep Australia free of the virulent strains of bluetongue virus.

Animals likely to be affected

Any ruminant animals such as sheep, cattle, buffaloes and goats.

Other diseases with similar signs

Virulent strains of bluetongue resemble other exotic diseases such as Foot and Mouth Disease and Vesicular Stomatitis. Bluetongue may also be mistaken for diseases that occur in Australia such as infectious bovine rhinotracheitis or BVDV(mucosal disease). Any outbreak of disease resembling bluetongue should be reported promptly to a veterinarian for a thorough investigation.

Confirming the diagnosis

Laboratory testing of blood samples indicates whether an animal has had contact with bluetongue virus. Laboratory testing of other samples can identify and type the bluetongue virus.

Spread of the disease

Bluetongue virus is transmitted from animal to animal by biting midges from the Culicoides family. These midges feed on infected animals and the virus multiplies in their salivary glands before being injected into another animal. Australia has several different types of Culicoides midges, each with a different distribution, but all are primarily located in northern Australia.

Treatment

Infectious bovine rhinotracheitis

What to look for

Clear discharge from their nostrils which may become cloudy and profuse

Drop in milk production
Inflamed eyes
Ulcers in the mouth

Laboured breathing

Not fatal unless there are complications such as bacterial infections

Cause

A herpes virus.

Animals likely to be affected

Most often seen as an outbreak in two year old cows but can occur in any age group. Outbreaks may be triggered by stressful situations such as transport or crowding.

Other diseases with similar signs

BVDV/Mucosal disease.

Confirming the diagnosis

Virus can be isolated from swabs of infected animals. Two blood samples collected several weeks apart can be tested to see if the level of antibodies to IBR increases.

Spread of the disease

The IBR virus is usually passed from cow to cow without causing disease. If a group of animals that have not previously encountered the virus and are stressed by such things as transport or introduction to the dairy herd an outbreak may occur. Animals usually stay infected with the virus for life and can spread it to animals that have not previously been exposed.

Treatment

Treatment is usually not required unless animals are seriously ill. If so, they should be isolated, given good nursing support and anti inflammatories. If bacterial infections are suspected, treat animals with antibiotics.

Risk factors

Introducing cattle from outside the herd

Transportation, overcrowding or other stresses

Prevention

Maintaining a closed herd reduces the risk of introducing IBR virus but the virus is widespread in cattle populations and may be present in herds without clinical disease. If an outbreak occurs, isolate infected animals to reduce the spread of the virus to vulnerable animals. Vaccines can be used to if there is reason to believe that animals are vulnerable to IBR e.g. entering a feedlot.

Gut form:

May affect individual animals or occur as an outbreak
Much milder changes to the nostrils, eyes and mouth seen
Animals rapidly develop profuse diarrhoea and die quickly

Cause:

A virus that is normally found in sheep without causing clinical signs of disease

Spread of the disease

Most sheep are infected with the virus which is secreted in their nasal secretions. It is not clear how cattle become infected but the disease rarely occurs in cattle that do not have contact with sheep. Some cattle appear to become infected without showing any clinical signs but it is believed that there is no transfer of MCF virus between cattle.

Animals likely to be affected

Malignant Catarrhal Fever is an unusual condition that is most often seen in yearling animals. Wild and domesticated deer are also susceptible.

Other diseases with similar signs

May resemble some forms of Bovine Virus Diarrhoea mucosal disease (caused by bovine pestivirus) or exotic diseases such as Foot and Mouth Disease.

Confirming the diagnosis

Any suspected case of MCF should be investigated by your vet to rule out the possibility of the Foot and Mouth Disease or other similar diseases that do not occur in this country.

Treatment

There is no treatment for MCF and so infected animals should be humanely killed.

Risk factors

Running sheep and cattle together. There is no vaccine for MCF and no specific preventive measures.

Initiatives

Dairy Feed Tools is a complete feed management toolset for dairy farmers and managers. Feed planning, cost and resource management backed by Australian feed and pasture data to most accurately reflect the needs of your herd